DefinitionNail abnormalities are problems with the color, shape, texture, or thickness of the fingernails or toenails.Alternative NamesBeau's lines; Fingernail abnormalities; Spoon nails; Onycholysis; Leukonychia; Koilonychia; Brittle nailsConsiderationsJust like the skin, the fingernails tell a lot about your health.Beau's lines are depressions across the fingernail. These lines can occur after illness, injury to the nail, and when you are malnourished.Brittle nails are often a normal result of aging. However, they also may be due to certain diseases and conditions.Koilonychia is an abnormal shape of the fingernail. The nail has raised ridges and is thin and curved inward. This disorder is associated with iron deficiency anemia.Leukonychia is white streaks or spots on the nails.Pitting is